Matrix for use in dentistry



' Nov. 24, 1931. R, FU T 1,833,247

MATRIX FOR USE IN DENTISTRY Filed Sept. 12, 1929 W INVENTOR Patented Nov. 7 24, 1931 UNITED T Application filed September 12, 1929, $eria1 No. 392,221, and in dermanysepteinlierfil 92 7 My invention relates to improvements in matrices for use in dentistry, and more particularly in matrices of the type used for covering the cavity of a tooth while fillingthe same. As now constructed such matrices consist of sheet metal rings or open sheet metal rings adapted to be placed around the sick tooth. The object of the improvements is to provide a matrix which is simple in construction, which fits on teeth of any size, and which provides a close covering for the cavity to be filled. With this objectin view my invention consists in constructing the matrix in the form of a thin elastic plate of a suitable material such as steel adapted to be placed between the sick tooth and the adjacent tooth and provided along its vertical margins with ribs or similar projections adapted to bear on the healthy tooth and to press the'plate into close contact with the sick tooth. My invention also relates to a tool suitable for placing the matrix in position on the sick tooth. V

Other objects of the improvements will appear from the following description.

For the purpose of'explaining the invention an example embodying the same has been been shown in the accompanying drawings in which the same reference characters have beenused in all the views to indicate corresponding parts. In said drawing,

Fig. 1 is a sectional plan view of the matrix taken on the line 1-1 of Fig. 3,

Fig. 2 is a sectional elevation taken on the line 2- 2 of Fig. 1,

Fig. 3 is an elevation showing the matrix as seenfrom the side of the healthy tooth,

Fig. 4 is a perspective view showing the sick tooth, the adjacent healthy tooth and the matrix brought into position for covering the cavity of the sick tooth, and

Fig. 5 is a perspective view showing a tool used for bringing the matrix into position. f r

In the example shown in the drawings the matrix consists of a thin plate 1 made from thin sheet metal such as steel and provided along its vertical margins with ribs or similar projections 2 provided between their top and bottom ends with recesses 3. At their inner outwardly,iso;that the ribs are crescent,-

at the bottom sides of the ribs, and it will be v I understood that when placing the matrix between upper teeth it is reversed so that the V cavity 4 bears on the gum.

The manner of usin the matrix has been illustrated in Fig. 4.; in the said figure the plate 1 is placed between a healthytooth 5 l and the sick tooth 6 so as to cover the cavity T 7. The ribs 2 bear on the healthy tooth and they .press the platel laterally and into close 7 contact with the sicktooth 6, the plate being slightly curved by the pressure of. the ribs. i

If necessary cotton'may be pushed through 7 the recesses'3and between the'bevelled portions 11 of the ribs 2and the healthy tooth 5 for, securely pressing the plate 1 on the tooth 6. The figures show screws 12 screw ing in bores 13 of the ribs. By screwing the said screws more or less inwardly and into engagement with the healthy tooth the plate- 1 maybe pressed on the sick t th fo u ely v r V closing the cavity.

For pressing the matrix on the sick tooth It: 1

use an angular tool shown in Fig. 5, the said tool comprising a handle 8 and a portion 9 in the form. of a spade bent laterally from the handle. The said spade portion may be placed between the plate 1 and the tooth 5, and thereafter the spade is slightly turnlrlad for pressing the plate 1 towards the toot 6.

I In describing the invention reference "has- I been made to the manufacture of the matrix 9'5. from sheet steel. But I wish it to be understood that myinvention is not limited to this feature, and that the matrix maybe manna factured from other suitable material such as celluloid or other cellulose products, 7

I claim: I 1. A dental matrix comprising a thin elastic'plate' for insertion in the space vbe- I tween two teeth and inelastic ribs on one face of said plate, said ribs having recesses to facilitate the introduction of material through the ribs.

2. A matrix as claimed in claim Lin which the plate is 'coneavo' convex cross sectionally and the ribs project from the convex face thereof and serve to hold the plate in such fl xed condition. d T

3. A matrix as claimed in claim 1., in which f the bottomsof the recesses in the ribs are 15 beve11ed:.;t0ward theplate. I I

.o fl, A matrix as claimed in claim 1, in which the ribsare provided ion'the sides opposed to the whenthe matrix is inuse, with recesses for spanning 'the' gum. M20 5; 1 A matrix as claimed in claim 1, in which the-opposing: sides ofthe ribs are convex in fOIII'1. iii-testimony whereof I hereunto afiix my 

